1. Field of the Invention
The invention relates to an additive manufacturing apparatus.
2. Description of Related Art
In recent years, an additive manufacturing apparatus has attracted attention. The additive manufacturing apparatus manufactures a laminated object having a three-dimensional shape by irradiating a powder material made from an inorganic material or an organic material with a laser beam so that the powder material is sintered or melted and solidified. To be specific, a step of forming a powder layer by spreading a powder material over a stage, and a step of forming a hardened layer are repeated. The hardened layer is formed by irradiating a given region of the powder layer with a laser beam so as to sinter or melt and solidify the powder layer. Therefore, it is possible to manufacture an object having a three-dimensional shape by laminating and integrating a number of hardened layers.
An additive manufacturing apparatus is disclosed in Japanese Patent Application Publication No. 2010-89438 (JP 2010-89438 A). The additive manufacturing apparatus includes an irradiation part that irradiates a powder material on a stage with a laser beam, a stage moving mechanism that moves the stage, a powder feeding part that feeds a powder material on the stage, and a powder storage part that stores the powder material. In the additive manufacturing apparatus disclosed in JP 2010-89438 A, a powder material is transferred from the powder storage part to the powder feeding part by using a pipe, and the powder storage part is arranged on a vertically lower side of the powder feeding part.
Like an additive manufacturing apparatus 100 shown in FIG. 11, in a case where a powder feeding part 36 is arranged on a vertically upper side of a powder storage part 40, it is possible to transfer a powder material from the powder storage part 40 to the powder feeding part 36 by sucking the powder material from the powder feeding part 36 side. In the additive manufacturing apparatus 100 having the above-mentioned structure, a pipe 143, which connects the powder feeding part 36 with the powder storage part 40, extends in the vertical direction. The details of the additive manufacturing apparatus 100 are given later.
However, when suction of the powder material is stopped after the powder material is transferred from the powder storage part 40 to the powder feeding part 36, the powder material inside the pipe 143 that extends in the vertical direction falls freely. At this time, when the powder material falls from a high position (for example, an upper end 142a of the pipe 143), an impact of collision between the powder materials becomes great, and the powder materials agglutinate with each other. When the powder materials agglutinate with each other, a mass of each aggregate increases, thus causing a problem that the agglutinated powder material cannot be transferred when the suction is resumed.